Numerical Analysis of Elasto-Plastic Adhesively Single Step Lap Joints with Cohesive Zone Models and Its Experimental Verification

Abstract

Adhesive bonding method is used as an alternative to mechanical bonding methods, and it is frequently used in automotive, space and aviation industries. In the present study; the displacement and failure load capacity characteristics of single step lap joint was measured experimentally and compared with results of finite element (FE) analysis. In addition, the change in the length and the thickness of the material and adhesive in this joint type, stresses on the adhesive was examined by numerical analysis that have affected. Also, the effects of overlap length and material thickness on the stresses in adhesive were examined with numerical analysis for the single step lap joint. AA2024-T3 aluminum alloy adhered material and double component DP460 structural adhesive was used as adhesives in the single step lap joint. In the numerical analysis of this joint type, two different material models including multilinear isotropic hardening (MISO) and cohesive zone model (CZM) were used in the adhesive layer. During the experimental tests, two cameras were used to measure the displacements and crack propagations. As a result, the data obtained from the numerical analysis were compared to the experimental data of the single step lap joint type, the use of CZM in the adhesive region was found to be very important in terms of compliance. Thus, the difference between CZM and MISO results in terms of damage load in adhesive is 7 %, while this difference is 32 % in terms of displacement. Also, it has a great importance to get the displacement data via a video extensometer for the compatibility of FE and experimental analyses. Another result obtained from the study is that changing the material thickness, the adhesive thickness and the overlap length in the joint, changes the stress concentrations and shear stresses at the ends of the overlap area.